'imbalance' originates from the negative prefix 'im-' (a variant of Latin 'in-') combined with the word 'balance' (from Old French 'balance' and Late Latin 'bilancia'), where 'bi-' meant 'two' and the root referred to a pair of scales.

'imbalance' was formed in English by adding the negative prefix 'im-' to 'balance' (itself from Old French 'balance', from Late Latin 'bilancia'). Over time this produced the English word 'imbalance' used from early modern English onward.

Initially it referred specifically to a lack of physical balance (e.g., uneven scales); over time it broadened to mean any lack of equilibrium or proportionality in systems, distributions, or conditions.